Apparatus for forming coverings and the like



March 1, 1938 H. M. PRYALE ET AL APPARATUS FOR FORMING COVERINGS AND THE LIKE Filed Aug. 9, 1955 4 Sheets-Sheet 1 ATTORNEYS N. VEKO m O 3 R N M M mu L MT SW Mama 59 H4 M.'PRYALE ET AL.

APPARATUS FOR FORMING COVERINGS AND THE LIKE,

Filed Aug. 9, 1935 4 Sheets-Sheet 2 INVENTORS ATTORNEYS HARRY WLPRYALE SAMUEL C.CLARK WILLIAM S.VROOMAN March 1, W38. H. M. PRYALE 5-i- AL 2,109,908

' APPARATUS FOR FORMING COVERINGS AND THE LIKE Filed Aug. 9, 1935 4 Sheets-Sheet 5 INVENTORS HARRY M. PRYALE Fig.6. SAMUEL c. CLARK WILLIAM S. VROOMAN ATTORNEY s arch l, 1933.,

H. M. PRYALE ET AL.

APPARATUS FOR FORMING COVERINGS AND THE LIKE Filed Aug. 9, 1935 4 Sheets-Sheet 4 Q Q Q Q INVENTOR 5 HARRY M- PRYALE K R A L c C L F- U M A 8 WILLIAM SIVROOMAN TORNE Patented Mar. 1, 1938 UNITED STATES PATENT OFFICE APPARATUS FOR FORMING COVERINGS AND THE LIKE poration of Michigan Application August 9, 1935, Serial No. 35,532

15 Claims.

This invention relates to apparatus for manufacturing articles of predetermined contour from a deformable material.

More particularly, the invention contemplates an improved apparatus for manufacturing contoured rubber mats, although it will be apparent as this description proceeds that the invention may be employed, in whole or in part, to manufacture various diiferent types of articles or coverings having a predetermined contour.

In manufacturing contoured mats and the like on a production basis, it has been customary in the past to place a sheet of uncured rubber stock of the requisite size in a pressure chamber between a form or die, conforming in shape to the contour of the covering desired, and a diaphragm having suflicient flexibility to permit the same to be readily deformed against the stock by fluid pressure possessing the temperature required to vulcanize or cure the stock to the contour of the die. While it is possible to manufacture satisfactory coverings by the above practice, nevertheless, the latter hascertain definite limitations, and one of the most serious of these limitations is the inability of the diaphragm to deform sufficiently to force the stock into any sharp corners that may be incorporated in the pattern of the die. It necessarily follows, therefore, that there are certain types of contours that cannot be secured by apparatus embodying a diaphragm of the type previously set forth. In addition, the foregoing practice is objectionable from the standpoint of quantity production, not only be- 7 cause the diaphragms are relatively unserviceable and require the operation of the apparatus to be frequently interrupted for the purpose of replacement, but, also because a relatively long interval 7 of time is required for the heat of the fluid to be transferred through the diaphragms to the stock to be vulcanized. Furthermore, in cases where a plurality of fluid pressure chambers or units are. combined into a. single apparatus, such as illustrated in the Harry M. Pryale and Samuel C. Clark application, Serial No. 716,772, filed March 22, 1934, a plurality of flexible hose connections are required for each chamber and like the diaphragms must be frequently replaced. Replacement of the elements previously referred to is not only costly from the standpoint of maintenance of the apparatus, but, also necessitates discontinuing the operation of the entire apparatus, during the interval the elements are replaced or repaired, and this temporary delay materially reduces the productive capacity of the apparatus, The present invention has as one of its principal objects to eliminate the objections noted above in connection with the foregoing practice, by providing apparatus rendering it possible to not only eliminate the flexible diaphragms and consequent complications from the apparatus, but, to also 5 eliminate practically all flexible hose connections in cases where a plurality of fluid pressure chambers are combined in one apparatus. In accordance with this invention, the heated fluid under pressure is applied directly to the uncured stock and provision is made for the fluid under pressure admitted to the uppermost chamber of the apparatus to flow directly into the next succeeding chamber. This procedure permits the expensive rubber diaphragms, as well as the flexible hose connections employed in the past to be dispensed with, and has the effect of: (1) reducing the maintenance cost of the apparatus to the minimum; (2) materially increasing the productive characteristics of the apparatus, without in- 20 creasing the size of the latter, since the time required in the past to replace the diaphragms and hose connections is not only saved, but, also because the direct application of the heated fluid to the stock efiects a reduction in the vulcanizing time; (3) providing a uniform fluid pressure in each chamber, due to the fact that all of the chambers are in constant communication with each other; and, (4) obtaining a higher grade pro-duct because of the ability of the stock to flow into or properly fill the die cavities.

Another advantageous feature of the present invention resides in the provision of apparatus of the character previously set forth, embodying a plurality of units cooperating with each other in one position thereof to form a series of fluid pressure chambers and having provision for supporting a die of predetermined contour in each of the pressure chambers.

A further advantageous feature of the present invention resides in the novel means provided herein for clamping the marginal edges of a sheet of uncured material to the die and for effecting a seal around the marginal edges of the material to prevent the fluid under pressure introduced into the chamber from finding its way between the die and stock. In accordance with this invention, the combined sealing and clamping of the stock to the die is effected by differential pressure means utilizing the fluid pressure introduced into the chamber to efiect both of the above functions.

Still another advantageous feature of the present invention resides in the novel means provided for effecting .a fluid tight seal between the several units of the apparatus when these units are in their operative positions.

In addition, the present invention contemplates novel means for actuating the several units of the press and for clamping these units in their operative positions. This latter means, as well as the foregoing features and numerous other objects of the present invention will be made more apparent as this description proceeds, especially when considered in connection with the accompanying drawings, wherein:

Figure 1 is a side elevational view of apparatus constructed in accordance with this invention;

Figure 2 is a fragmentary front elevational view of the construction shown in Figure 1;

Figure 3 is a fragmentary sectional view illustrating one side of the apparatus shown in Figure 1 and featuring the guide means for the several units of the press;

Figure 4 is a view similar to Figure 3, showing the several units of the press in a different position;

Figure 5 is a fragmentary topplan view of the construction shown in Figure 1;

Figure 6 is a fragmentary rear elevation of the construction shown in Figure 1;

Figure '7 is a plan view of one of the units employed in the press featured in Figure 1;

Figure 8 is an enlarged sectional view taken substantially on the plane indicated by the line 8-8 of Figure '7;

Figure 9 is a View similar to Figure 8, featuring a slightly modified form of construction.

The method of manufacturing contoured coverings from a material containing rubber, in accordance with this invention, is relatively simple and consists generally in positioning a flat sheet of uncured stock of the required size upon a die shaped to correspond exactly to the desired contour of the covering to be formed. After the stock has been properly positioned upon the die, the marginal edges of the former are clamped to the latter, by means having the additional function of forming a seal around the margin of the stock to prevent fluid pressure from finding its way beneath the stock. Upon completion of the clamping operation, fluid under pressure having the temperature required to vulcanize the stock to the contour of the die is applied directly upon the top surface of the stock and the marginal sealing means is such that the fluid under pressure applied to the stock actually increases the efliciency of the seal. In quantity production, it is desired to form a plurality of contoured rubber coverings simultaneously, and this may be accomplished by the apparatus about to be described.

In general, the apparatus selected herein for the purpose of illustrating this invention is provided with a bottom header 2!! pivotally supported at the rear end thereof upon a shaft 2! for swinging movement from a position in a substantially horizontal plane indicated in Figure 1 by the dot and dash lines to the full-line position thereof shown in this figure, wherein the same is located in a plane inclined in an upward direction with respect to the horizontal. In addition, the apparatus is provided with an upper header 22 fixedly supported above the lower header in a plane parallel to the inclined plane of the latter by means of suitable frame work 23. Supported in superposed relation between the two headers is a plurality of forming units 24 of identical construction and mounted for pivotal movement independently of each other about the axis of the shaft 2|.

As shown in Figure 8, the forming units 24 c0- operate with each other in the operative or fullline positions thereof illustrated in Figure 1, to form fluid pressure chambers 25, and each unit is provided with a die 26 supported in the fluid pressure chamber formed by adjacent units in a manner to be more fully hereinafter set forth. In accordance with this invention, fluid under pressure is introduced into the top header 22 from a source of supply, through the medium of a conduit 26 and communication is established between the adjacent chambers 25, through a plurality of openings 21 having a combined area sufficient to insure a uniform pressure throughout the entire apparatus.

It will, of course, be understood that the several forming units must be in their uppermost or full-line positions shown in Figure 1 before the fluid under pressure is introduced into the press, and, in accordance with this invention, the units are successively moved about the axis of the shaft 2| from the dot-and-dash line positions thereof illustrated in Figure 1 to the full-line positions shown in the same figure. In actual practice, a sheet of uncured stock of the required size is placed upon the die 26 when the unit carrying the die is in its inoperative or dot-anddash line position shown in Figure 1. After the fluid-tight seal, about to be described, is operatively positioned with respect to the marginal edge of the sheet, the unit is moved upwardly into a position adjacent the header 22 and a sheet of uncured stock is similarly placed on the die carried by the next adjacent unit. The latter unit is then moved up to its operative position adjacent the unit aforesaid, wherein the die of the former unit cooperates with the die of the latter unit to form a fluid pressure chamber 25 above the stock. This procedure is followed until all of the units, including the header 20, are in their operative or full-line positions shown in Figure 1, and the fluid under pressure is then introduced into the chamber 25 formed by the several units to vulcanize the stock to the contour of the dies.

The means for independently moving the several units about the axis of the shaft 2| comprises a drum 3i) driven by a prime mover, such as the electric motor 3!, and operatively connected to the front or swinging side of each of the pivotally mounted units 24. In the present instance, the connection between the drum 30 and pivotally mounted units is effected by means of a flexible cable 32 having one end secured to the drum 30 in any suitable manner and having the opposite end successively reeved around pulleys 33 respectively carried by the front or swinging sides of the units 24. As shown in Figure 1, the cable 32 extends forwardly from the drum 3!] around a freely rotatable drum 34 journaled upon the top of the press at the forward end thereof and from the drum 34 the cable is reeved around the pulley 33 associated with the uppermost pivotally mounted unit 24. From the aforesaid pulley 33, the cable is again rotated around the freely rotatable drum 3d and is reeved around the pulley 33 at the forward end of the next adjacent unit 24. This method of connection is repeated with the remaining number of units 24 and after being passed several times around the drum 34 and a second drum 34', carried by the lower header 20, is secured to the machine frame as at 32. The arrangement is such that when the several units of the apparatus are in their inoperative positions shown by the dot-and-dash lines in Figure '1, initial rotationi of the drum 30 in the direction of-the arrow 35 causes the top unit 24 to move to its uppermost position adja- -cent the header 22 without disturbing the remaining units. However, as rotation of the drum is continued, the next adjacent units will successively move-into their uppermost positions, indicated by the full lines in Figure 1. understood, of course, that "any suitable means may be employed to interrupt the rotation of the drum after the uppermost unit is in its operative position so as to permit loading the unit beneath the same. It may also be pointed out at this time that the units are accurately positioned with respect to each other as they are moved to their operative positions, by means of guides 35f shown in Figure 3 as positioned at opposite sides of the press. 7 7

When the sections are in their operative posi- 'tions shown by the full lines in Figure 1, it is desired to positively hold the samein this position in order to prevent the reaction of the fluid under pressure in the chambers 25 from separating the units. The above is accomplished in the present instance by providing a plurality of bolts 36 oneach sideof the press having the upper ends thereof secured to plates 31 mounted upon the top frame structure for sliding movement in opposite directions in a plane parallel'to the inclined planeof the upper header ZZ. Upon reference to Figure 5, it will be noted that the bolts on one side of the press are secured to one of the plates 37, while the bolts at the opposite side of the press are secured to the other of the plates 31, so that asthe plates are moved toward each other from their outermost positions, the bolts 36 will be moved as a unit therewith toward the adjacent sides of the press. Referring again to Figure 1, it will be observed that the bolts extend downwardly from the plates perpendicular to the plane of sliding movement of the plates, and the lower end portion of each bolt is adapted to assume a position between the base portions of a pair of channel-shaped members 38 extending laterally outwardly from opposite sides of the lower header 2!! of the press; The extreme lower ends of the bolts are threaded for receiving the adjusting nuts 39, and the latter are flanged as at 4!! to form an abutment for the'oppositely extending flanges 4| on the channel-shaped members 58. It will, of course, be understood that the extent of sliding movement, of the plates 3'! is so determined that when the plates are in their outermost positions with respect to opposite sides of the press, the bolts will assume positionslaterally beyond the ends of the members 38, and when the plates are in their innermost positions,'the bolts move into locking position between the base portions of the channel-shaped members 38, wherein the flanges 49 on the adjusting nuts at the extremities of the bolts serve to prevent displacement of any one of the units from their operative positions. 7

While any suitable meansjmay be employed for actuating the plates 31 to eifectythe desired movement of the locking bolts, nevertheless, for the purpose of illustration, we have shown this means as comprising a rotatable screw '44 having the opposite ends threadedly engaged in the nuts 45 respectively mounted on the plates 31. As 7 top frame structure of the press.

prime mover 46 also suitably supported on the It is to be larger area than the area around the frame between Having described the general structure of the apparatus illustrated herein for carrying out the improved method of manufacturing contoured coverings from a material containing rubber, particular reference will now be made to the detailed construction of one of the unit's 24, since these units are preferably although, not necessarily, exactly the same in construction. As shown in Figure 8, each of the units 2% comprises a rectangular frame 50 having a plate 51 secured to the upper side of the frame and forming a support for the die 26 which is preferably, although, not necessarily, formed of aluminum alloy. The die 26 corresponds in shape to the contour it is desired to impart 'to the covering material 'to be formed, and of the die is covered by a suitable material 52 such as hard rubber. The hard rubber covering, of course, conforms to the contour of the die, and a design may be provided on the top surface of the covering 52 corresponding to a specifled pattern on the article to be formed. The die 25 and plate 5! preferably form a unit and the marginal edges of the hard rubber covering 52 are vulcanized or otherwise suitably secured to the top surface of the plate 5! beyond the die 26 so as to prevent the passage of fluid between the hard rubber cover and the plate. 1

As hereinbefore stated, the uncured rubber material to be vulcanized to the contour of the die 26 is placed upon the rubber covering 52 and the working surface the marginal edges of the material are clamped tothe die in such a manner as to form an effective seal around the marginal edges. The means for accomplishingthe above result comprises a frame .53 shown in Figure 7 as defining a slightly of the material to be vulcanized, but, as conforming in shape to the outline of the material. Referring again to Figure 8, it will be noted that the edge of the frame 53 adjacent the back of the press is hingedly connecte'd'to the plate 5| by means of a plurality of hinge units "designated by the reference character 54.. .Secured'to' the underside of the frame 53 and .co-extensive with the latter is a rubber sealing strip 55 having a Width substantially greater than the width of the frame 53. It will be apparent from -Figur'e 8, that the inner edge oftlie sealing strip 55 is adapted to overlap the covering material to bevulcanized, while the outer edge of the sealing strip is adapted to en'- gage the upper surface of the hard rubber covering 52 laterally beyond the marginal edges of the .material to be vulcanized, and the aforesaid edges of thesealing strip '55 i into engagement with the above mentioned surfaces by means of a plurality of spring fingers 55 arranged in juxtapositionto each other the lower side of the latter and the sealing strip. It will .served from Figure '8, that the central portion of the sealing strip 55 is reinforced by a strip 57 having an outline corresponding to the outline of thef-rame 53 and engagingthe underside of the sealing strip 55 between the side edges of the latter. The strip 51, sealing strip 55, and spring fingers 56 are secured .to the underside of the frame 53 as, a unit, by means of an auxiliary frame 58 also corresponding in outline to the frame 53 and secured thereto at spaced points,

through the medium of the fastener elements are normally urged also be ob- 59. The'frame 53, in addition to: carrying the r 1 sealingstrip assembly previously described, also carries ,a. plurality of spaced coil springs Gil "secured'to the "frame by the fastener elements 59 and having a length slightly greater than the height of the fluid pressure chamber 25 provided between the plates 5| of the adjacent units, so as to engage the plate 5| of the next adjacent unit upon relative movement of the units toward each other and thereby yieldably urge the marginal edges of the sealing strip 55 into engagement with the surfaces adjacent thereto.

With the foregoing construction, it will be observed that the combined clamping and sealing unit for the material to be vulcanized is movable as a unit with the frame 53 about the axis of the hinge units 54 connecting the frame 53 with the plate 5|. Hence, when it is desired to place a sheet of uncured rubber material upon the die, the frame 53 is merely moved upwardly about the axis of the hinge units a suflicient distance to permit properly positioning the sheet on the die, whereupon the frame is returned to its normal position and the unit is moved upwardly about the axis of the shaft 2| in the manner previously set forth to form a fluid pressure chamber 25 with the unit directly above the same. Incidentally, the aforesaid relative movement of the units causes the springs 60 to compress and initially clamp the material to be vulcanized to the die. After all of the units 24 have been properly loaded and moved to the full-line positions thereof shown in Figure 1, fluid under pressure is admitted to the uppermost unit through the conduit 26 and is uniformly distributed throughout each of the units by reason of the holes 21 formed in the plates 5 I The fluid under pressure admitted to each of the units, of course, serves to press the sheet of material to be vulcanized against the die and furthermore, is of such a temperature as to cure this material to the contour of the die. In order to insure proper contact of the sheet of material to be vulcanized with the die, it is necessary to provide for the escape of any air that may be trapped beneath the sheet, and this is accomplished in the present instance by forming a plurality of air bleeds 63 through the die. As will be observed from Figure 8, the air escaping through the bleeds 63 enters a chamber 64 beneath the plate 5| through a plurality of openings 65 formed in the plate 5|. The chamber 64 is formed by a plate 66 secured in spaced relation to the underside of the plate 5| and communicating with the atmosphere through a plurality of holes 51 formed. in the frame 50 of the unit.

It has been stated above that the fluid pressure in the chambers 25 cooperates with the springs 60 in deforming the strip 55 to provide an effective seal around the marginal edges of the covering to be vulcanized, and in order to obtain the differential pressure between the space beneath the strip 55 and the chamber 25 required to secure the above mentioned seal, communication is provided between the space beneath the strip 55 and the atmosphere. This is accomplished herein by forming openings 58 in the die, in such a manner that the openings establish communication between the space enclosed by the sealing strip 55 and the chamber 64, which as previously stated, communicates with the atmosphere through the openings 61.

Of course, it will be apparent that since the several units cooperate with each other in their operative positions to form fluid pressure chambers therebetween, some means must be provided for effectively sealing the joint between adjacent units, and this is accomplished herein by a sealing strip 10 formed of a flexible material such as rubber. A sealing strip 10 is secured to the bottom surface of each of the frames 50 and is continuous with the frame. The preferred cross sectional contour of the sealing strip 10 is shown in Figure 8, and, as will also be observed from this figure, the strip is secured to the frame 50 by a retainer strip H welded or otherwise suitably secured to the frame 50. The inner edge of the sealing strip 10 extends laterally inwardly beyond the corresponding edge of the retainer and is normally urged into frictional engagement with the plate 5| of the next adjacent lower unit, by means of the springs I2. The springs 12 are secured to the bottom of the frame 50 in juxtarelatlonship and also cooperate with the retainer H to secure the sealing strip 10 to the frame 50. From the foregoing description, it will be noted that the fluid pressure in the chambers 25 cooperates with the springs 12 in effecting a tight seal between the strip 10 and the adjacent plate 5|.

The embodiment of the invention shown in Figure 9 illustrates a unit 24' of slightly different construction, although it is similar in principle of operation to the one previously described. In detail, the frame 50 of the unit in Figure 9 is substantially channel-shaped in cross section and is so constructed that the channel of the frame opens inwardly toward the fluid pressure chamber 25. Secured in the channel of the frame 50' between the flanges of the channel and extending inwardly beyond the inner ends of the flanges is a plate 15 for supporting the die 16. The die I6 differs from the die 26 previously described, in that the operating surface thereof instead of being rubber covered to avoid adhesion of the stock, is plated with a suitable metal, such as tin for example.

The stock to be vulcanized to the contour of the die-is clamped to the latter beyond the operating portion of the same, by means of a continuous rubber strip 11 secured to the underside of a frame 53' identical in construction to the frame 53 described in connection with the foregoing embodiment of this invention. The rubber strip 11 is yieldably urged into clamping engagement with the stock, by means of coil springs 60 cooperating with the underside of the unit directly above, in the same manner as the coil springs 60 previously referred to. In the present embodiment of the invention, it is also desired to provide an effective seal between the marginal edge portions of the stock and die. This is accomplished in the present instance by forming a continuous groove 18 in the die having air bleeds 19 communicating with the interior of a discharge chamber formed by a tube 8| welded or otherwise suitably secured to the underside of the die. As will be observed from Figure 9, the groove 18 in the die assumes a posi tion laterally inwardly with respect to the clamping strip 11, and the arrangement is such that when the fluid under pressure is admitted to the chamber 25 above the stock, the portion of the latter extending over the groove is displaced into the groove. In this connection, it may be pointed out that the chamber 80 communicating with the groove 18 also communicates with the atmosphere through the medium of the conduits 82 so as to afford the required pressure differential to permit the portion aforesaid of the stock to be readily displaced into the groove 18.

With the foregoing exceptions, the apparatus containing the units 25 and the operation of this apparatus may be identical to the one previously plate 25 is apertured as at 83 aioopo from the apparatusby a valve controlled conduit 83' communicating with the*upper header of the apparatus, and any condensate accumulating in the units is permitted todrain through the openlngs at the rear sides of the units to the lower header of thegapparatus where it discharges in any suitable, manner..

.Thus from the foregoing, it will be observed thatpvve have provided a relatively. simple method and: 1' apparatus for lvulcanizing uncured rubber stockto. a predetermined desired contour. It

will also be apparent that our improved apparatus materially reduces maintenance." cost by the elimination of th-evrelatively unserviceable diaphragms heretofore employed in the process re-' ished covering and thereby, oifers the possibility of eliminating the:edge"trimming operation required with prior methods of manufacture; ;In addition, the elimination of the rubber diaphragms previously discussed'in'connection with prior practice, offers the'possibility of forming a superior product, since it permits accurately duplicating the contour of diesembodying sharp corners. Although two specific'embodiments'of the invention. have been described somewhat in detail, it should beunderstood that various changes may be made'in the several parts of the apparatus, without departingfrom the principles set'forth herein, and,'accordingly; reservation is made'to make such changes as may come within the purview of the accompanying claims.

What we claim as our invention is:

1. In apparatus for'forming a covering of predetermined contour from deformable stock, a

fluid pressure chamber, a die supported. in the chamber having a working face corresponding in shape to the '.desiredcontour of the covering arid forming ai support for the stock, means for-in troducing fluid pressure into thechamber in direct contact with the stock. to deform the same to the contour of the die;.and'means' for effecting a fluid-tight seal between the marginaledge porand defining a space around the marginal edges of the stock communicating with an area of less pressure than the pressure in the chamber.

2. In apparatus for forming a covering of predetermined cont'our from vulcanizable stock, a

units when the Inthis connection, it is to be noted that'the inclination ofthe several, 20

. determined contour fluid pressure chamberja diesupported in the chamber having aworkingface conforming in shape to the desired contour of the coveringand forming a support for surface for the stock laterally beyond; the marginal edge of the latter, and means establishing compressible strip and an area ofless pressure than the pressure existing in the chamber. 1 g

3'. In apparatus for forming a covering of pre determined" contour from vulcanizable stock, a

determined contour from vulcanizable 7 stock, a-

fluidpressure chamber, a. die supported in the having a working face-corresponding in shape tothe desiredcontour of the covering and forming a support for the stock, means for introducing fluid under;

ginal edges of the stock and i ing surface, a frame carrying the sealing means mounted for swinging movement toward and away from the working face of the die,and yieldable. means acting upon the frame to initially i of the stock against clamp the marginal edges the adjacent supporting surface. i

5. In apparatus for forming a covering ofprefrom deformable stock, a fiuid pressure chamber, a, die supported in the chamber having a Working face conforming" in shape to the desired contour of the covering and forming a support for the stock, means for introducing fluid pressure into the chamber in direct contact with the stock to deform the same to the contour offthe die, means coacting with the fluid under pressure in'the chamber to effect a fluid-tight seal between the marginal edge portions of the stock and adjacent supporting surface, and auxiliary means for initially effecting the aforesaid seal fluid pressure in said chamber. i

6. In apparatus forforming a covering of predetermined contour from vulcanizable stock, a fluid. pressure chamber; adie supported in the chamber having a shape to the desired contour of the covering and forming a support for the stock, means for introducing fiuid'pressure into the chamber in direct contact with the stock, means foreffecting the stock,-means for introducing fluid underpressure intogthe chamber in direct contact with the stock, means inwthefiuidpressure chamber for effecting a seal between, the

adjacent supportprior'to the introduction of the 60 working face conforming in other marginal edge portion engageable with the supporting surface for the stock laterally beyond the marginal edge of the stock and providing a space adjacent the marginal edge of the stock communicating with a zone of reduced pressure, and means acting upon the compressible strip prior to the introduction of fluid under pressure in the chamber to initially deform the strip.

7. In apparatus for forming a covering of predetermined contour from vulcanizable stock, a fluid pressure chamber, a die supported in the chamber having a working face conforming in shape to the desired contour of the covering and forming a support for the stock, means for introducing fluid pressure into the chamber in direct contact with the stock, means for effecting a fluidtight seal between the marginal edge portions of the stock and adjacent supporting surface including a compressible strip exposed to the fluid pressure in the chamber and having one marginal edge portion overlapping the marginal edge portion of the stock, said strip having the other marginal edge portion engageable with the supporting surface for the stock laterally beyond the marginal edge of the stock providing a space adjacent the marginal edgeof the stock communicating with a zone of reduced pressure, and a frame carrying the deformable strip mounted for swinging movement toward and away from the die.

8. In apparatus for forming a covering of predetermined contour from vulcanizable stock; a plurality of units arranged in superposed relation and eachunit embodying a die provided with a working face corresponding in shape to the desired contour of the covering and adapted to support a sheet of stock to be vulcanized, the dies of adjacent units cooperating with each other to form fluid pressure chambers above the working faces of the dies, and means for introducing fluid under pressure into each of said chambers.

9. In apparatus for forming a covering of predetermined contour from vulcanizable stock, a plurality of units arranged in superposed relation and mounted for relative movement toward and away from each other, a die in each unit having a working face corresponding in shape to the desired contour of the covering to be formed and adapted to support a sheet of stock to be vulcanized, means for introducing fluid under pressure into the units above the working faces of the dies when the units are in operative position with respect to each other, and means responsive to the introduction of fluid pressure into the units for effecting a fluid-tight seal between the units.

10. In apparatus for forming a covering of predetermined contour from vulcanizable stock, a plurality of separable units arranged in superposed relation when in operative position, a die in each unit provided with a working face corree sponding in shape to the desired contour of the covering to be formed and adapted to support a sheet of stock to be vulcanized, the dies of adjacent units cooperating with each other when said units are in superposed relationship to form fluid pressure chambers above the working faces ofthedies, means for introducing fluid under pressure into the chambers, and means for effecting a fluid-tight seal between adjacent units.

11. In apparatus for forming a covering of predetermined contour from vulcanizable stock, a plurality of units arranged in superposed relation and each unit embodying a die provided with a working face corresponding in shape to the desired contour of the covering to be formed and adapted to support a sheet of stock to be vulcanized, means for introducing fluid under pressure into the units above the working faces of the dies, means responsive to the introduction of fluid pressure into the units for effecting a fluid-tight seal between the units, and additional means also responsive to the introduction of fluid pressure into the units for effecting a fluid-tight seal between the marginal edges of the stock and the adjacent supporting surfaces.

12. In apparatus for forming a covering of predetermined contour from vulcanizable stock, a plurality of separable units arranged in superposed relation when in operative position with respect to each other, a die in each unit provided with a working face corresponding in shape to the desired contour of the covering and adapted to support a sheet of stock to be vulcanized, means for introducing fluid under pressure into the units above the working faces of the dies, and means responsive to relative movement of the units into operative relationship to effect a fluid-tight seal between the units.

13. In apparatus for forming a sheet of predetermined contour from vulcanizable stock, a plurality of units forming chambers and supported for relative movement from an operative position in superposed relationship to an inoperative position, a die in each unit provided with a working face corresponding in shape to the desired contour of the sheet and adapted to support the stock to be vulcanized, the chambers formed by the units communicating with each other in the operative positions of the units, and means for introducing fluid under pressure into one of the chambers to build up a fluid pressure in each of the chambers above the working faces of the dies.

14. In apparatus for forming a sheet of predetermined contour from vulcanizable stock, a plurality of units forming chambers and supported for relative movement from an operative position in superposed relationship to an inoperative position, a die in each unit provided with a working face corresponding in shape to the desired contour of the sheet and adapted to support the stock to be vulcanized, the chambers formed by the units communicating with each other in the operative positions of the units, means for introducing fluid under pressure into one of the chambers to build up a fluid pressure in each of the chambers above the working faces of the dies, and means rendered effective by the fluid pressure in each of the chambers to seal the marginal edges of the sheet of stock to the adjacent surface of the die.

15. In a press of the character described, a tier of co-operating movable pressure members, and means for actuating said members for opening and closing the press comprising sheaves connected with the members and a cable extending over the sheaves.

HARRY M. PRYALE. SAMUEL C. CLARK. WILLIAM S. VROOMAN. 

